This has been a good event for the past couple of years that I've attended. A good mix of all sorts of classics up to 1990's cars. Very relaxed atmosphere in the grounds of some posh gaff near Oxford.
Various 'pride of ownership' type events through the day add to the fun. My 968 got 2nd place last year in the 1990's cars category (lost to a Rover 800
).Here's the link if you're looking for somewhere to take the Porsche this weekend: http://www.blenheimpalace.com/whats-on/events/655.html